If $x^y=e^{x-y}, x> 0, $ then $\frac{dy}{dx}$ is equal to: |
$-\left[\frac{log_ex}{(1+log_ex)^2}\right]$ $\frac{log_ex}{(1+log_ex)^2}$ $-\frac{log_ex}{1+log_ex}$ $\frac{log_ex}{1+log_ex}$ |
$\frac{log_ex}{(1+log_ex)^2}$ |
The correct answer is Option (2) → $\frac{log_ex}{(1+log_ex)^2}$ $x^y=e^{x-y}$ $y=\log_xe^{x-y}$ $=\frac{\log_ee^{x-y}}{\log_ex}=\frac{x-y}{\log x}$ $∴\frac{dy}{dx}=-\frac{dy}{dx}\log x-\frac{(x-y)}{x}×\frac{1}{(\log x)^2}$ $\frac{dy}{dx}(1+\log x)=\frac{y-x}{x(\log x)^2}$ $\frac{dy}{dx}=\frac{\log_ex}{(1+\log_ex)^2}$ |